Imaging with light is gaining popularity in biomedical applications. One currently popular light imaging application involves the capture of low intensity light from a biological sample such as a mouse or other small animal. This technology is known as in vivo optical imaging. A light emitting probe inside the sample indicates where an activity of interest might be taking place. In one application, cancerous tumor cells are labeled with light emitting reporters or probes, such as fluorescent proteins or dyes.
Photons emitted by fluorescent cells scatter in the tissue of the mammal, resulting in diffusive photon propagation through the tissue. As the photons diffuse, many are absorbed, but a fraction reaches the surface of the mammal—and can be detected by a camera. Light imaging systems capture images that record the two-dimensional (2D) spatial distribution of the photons emitted from the surface.
However, the desirable imaging information often pertains to the location and concentration of the fluorescent source inside the subject, particularly a three-dimensional (3D) characterization of the fluorescent source. Reliable techniques to convert the 2D information in the camera images to a 3D characterization of the fluorescent probe concentration are desirable.